The term "measurement of distances to, position, and/or displacements and physical properties of, a medium," as used herein, is intended to encompass the performance of measurements or sensing of micro- and/or macro-movements, which can be utilized to construct microphones, hydrophones, accelerometers, pressure/vacuum gauges, temperature sensors, displacement meters, sensors measuring thickness of micro-coating, surface characteristics of silicon wafers, high accuracy measurement of movements and positioning of different kinds of shafts, gauges, valves, sliding tables and the like.
Sensors of the general type of the present invention and a method of measuring are known from U.S. Pat. No. 5,771,091 the teachings of which are incorporated herein by reference. In cases where the location to be measured is very close to the sensor, however, the utilization of optical fibers as light guides presents a technical problem, as the optical fibers are very small, e.g., up to a few millimeters; processing such small and delicate guides must be carried out in special ways.
It is thus a broad object of the present invention to overcome the above-mentioned difficulty and to provide light-based sensors utilizing solid light guides.